I personally don't invest in company FDs, so I have not much idea. I have checked on Google and Mahindra FD is assigned AA+ rating from CRISIL indicating High Safety.
5 Nov'2009 - CRISIL has revised its rating outlook on Mahindra & Mahindra Financial Services Ltd’s (Mahindra Finance’s) debt programmes and bank facilities to ‘Stable’ from ‘Negative’.